Doing a first stab at getting chef metrics in here

Still needs work as the bson doc seems to be corrupt.
Fix for issue #35 and setup stuff to work with drone.io

With this commit we are switching from Travis to drone.io for doing
automated building and testing
Fixed issue #39

And reversed the version to be 0.4.2 as 0.5.0 is only a valid version
when adding support for safechefmetrics (which is only partly finished
in this release)
Fixing some additional errors after testing
Bugfixing to get a clean build
Merge pull request #48 from svanharmelen/dev

Fixing several issues and moving to drone.io for CI